The invention relates to locks and more particularly a pin tumbler cylinder lock that can be re-keyed to be opened by a key whose teeth can be arranged in a mating longitudinal sequence to open the lock. In the past most pin tumbler cylinder locks were not capable of being re-keyed. As a consequence, if a person lost his key, it was often necessary to replace the entire lock or require the services of a locksmith.
The Hori U.S. Pat. No. 3,432,757 is directed to a multiple key lock having a change key mechanism. It is a conventional pin-type key operated lock having a blocking needle originally positioned in a cavity in the shell adjacent the rotatable core locking certain inoperable pins, with the shell parts thereof inoperable in the shell and free of blocking a remaining operable pin. An original master key properly positions the operable pin and the core pins parts in the inoperable pins for rotation of the core while a back key surface prevents the blocking needle from moving radially into the key slot during rotation. A change key is functionally identical to the master key, except for a recess on its back surface receiving the blocking needle therein for removal from the core with the change key. This frees all of the pins for subsequent rotation of the core only by a properly formed final key.
In more recent years, improved pin tumbler cylinder locks have been designed which allow a combination to be changed. The Burlingame U.S. Pat. No. 3,910,083 discloses a combination changing cylinder lock that allows the service key to be changed externally without access to the lock interior. His cylinder lock has tumbler pins comprising a plurality of interlocking segments, the interfaces of adjacent pairs of segments being such that the adjacent segments may be placed in shear, blocking, or passover orientations dependent upon their relative rotations. To change the combination of the service key, a master key is used to place each pair of adjacent pin segments in the shear orientation. A service key having the desired new combination is then used to operate the lock and the adjacent pin segment pairs are selectively placed in the locking or passover orientations depending upon the requirements of the new combination.
The Monahan U.S. Pat. No. 4,712,401 relates to a method of re-keying a pin tumbler cylinder lock having tumbler pins, driver pins and at least one master pin without disassembly of the lock apparatus or removal or replacement of any master pins therefrom.
The Shen U.S. Pat. No. 4,732,023 is directed to a modifiable cylinder. The primary object of the invention is to provide a modifiable cylinder in which the combination of pin tumblers in disks of the cylinder are changed by a designated key so that the original cylinder will become useless and a lock can be operated only by this designated key.
The Silvern U.S. Pat. No. 3,243,979 relates to an improved key that can be varied into configurations to fit different lock arrangements.
The Urrestarazu-Borda U.S. Pat. No. 4,545,226 is directed to a combination key that permits the opening of various locks with a single key.
It is an object of the invention to provide a novel lock and key assembly that has a key whose teeth are removable and rearrangeable in various sequences.
It is also an object of the invention to provide a novel universal lock and key assembly that has structure for temporarily locking its top pins in its top pin housing portion while its bottom pins are being removed.
It is another object of the invention to provide a novel universal lock and key assembly that has structure for removing its bottom pins from its tubular sleeve without disassembling these two members from each other.
It is an additional object of the invention to provide a novel lock and key assembly that is economical to manufacture and market.
It is a further object of the invention to provide a novel lock and key assembly that is can have the teeth of its key and the bottom pins of its bottom pin cylinder rearranged by an untrained do-it-yourselfer.